Ferroelectric-Like Behavior In Tan/High-K/Si System Based On Amorphous Oxide

Thin-film ferroelectric of HfO2-based has gained broad interest for non-volatile memories. The traditional theory with respect to doped hafnium oxide is based on the polycrystalline structure of the Pcb2(1) non-centrosymmetric orthorhombic phase. While amorphous oxides also show ferroelectricity, which cannot be explained by the traditional theory. Here, ferroelectric-like behavior is observed in the amorphous oxide-based TaN/high-k/Si system. Through strategically modulating the atomic layer of deposition conditions of the high-k oxides, the evolution from paraelectric to ferroelectric-like behavior is seen in TaN/Al2O3/Si capacitors. The interface chemistry of these stacks is systematically studied via in situ angle-resolved X-ray photoelectron spectroscopy. A mechanism for the ferroelectric-like behavior is proposed based on interface ions-vacancies displacement. This work sheds light on physics in ferroelectric-like thin film devices.